SPARTA (7 Jul 2014)
# advect particles via VSS collisional flow on a uniform grid
# particles reflect off global box boundaries

variable            x index 10
variable            y index 10
variable            z index 10

variable            lx equal $x*1.0e-5
variable            lx equal 20*1.0e-5
variable            ly equal $y*1.0e-5
variable            ly equal 20*1.0e-5
variable            lz equal $z*1.0e-5
variable            lz equal 25*1.0e-5

variable            n equal 10*$x*$y*$z
variable            n equal 10*20*$y*$z
variable            n equal 10*20*20*$z
variable            n equal 10*20*20*25

seed	    	    12345
dimension   	    3
global              gridcut 1.0e-5

boundary	    rr rr rr

create_box  	    0 ${lx} 0 ${ly} 0 ${lz}
create_box  	    0 0.0002 0 ${ly} 0 ${lz}
create_box  	    0 0.0002 0 0.0002 0 ${lz}
create_box  	    0 0.0002 0 0.0002 0 0.00025
Created orthogonal box = (0 0 0) to (0.0002 0.0002 0.00025)
create_grid 	    $x $y $z
create_grid 	    20 $y $z
create_grid 	    20 20 $z
create_grid 	    20 20 25
Created 10000 child grid cells
  parent cells = 1
  CPU time = 0.00244904 secs
  create/ghost percent = 84.1511 15.8489

balance_grid        rcb part
Balance grid migrated 8560 cells
  CPU time = 0.0103831 secs
  reassign/sort/migrate/ghost percent = 17.6142 0.406429 14.023 67.9564

species		    ar.species Ar
mixture		    air Ar vstream 0.0 0.0 0.0 temp 273.15

global              nrho 7.07043E22
global              fnum 7.07043E6

collide		    vss air ar.vss

create_particles    air n $n
create_particles    air n 100000
Created 100000 particles
  CPU time = 0.00337505 secs

stats		    10
compute             temp temp
stats_style	    step cpu np nattempt ncoll c_temp

# first equilibrate with large timestep to unsort particles
# then benchmark with normal timestep

timestep 	    7.00E-8
run                 30
Memory usage per proc in Mbytes:
  particles (ave,min,max) = 2.05994 2.05994 2.05994
  grid      (ave,min,max) = 1.83113 1.83113 1.83113
  surf      (ave,min,max) = 0 0 0
  total     (ave,min,max) = 3.89107 3.89107 3.89107
Step CPU Np Natt Ncoll temp 
       0            0   100000        0        0    273.04554 
      10  0.049942017   100000    96350    70567    273.04554 
      20  0.098089933   100000    98992    70803    273.04554 
      30      0.14624   100000   100506    70698    273.04554 
Loop time of 0.146271 on 8 procs for 30 steps with 100000 particles

Particle moves    = 3000000 (3M)
Cells touched     = 14412987 (14.4M)
Particle comms    = 542856 (0.543M)
Boundary collides = 557486 (0.557M)
Boundary exits    = 0 (0K)
SurfColl checks   = 0 (0K)
SurfColl occurs   = 0 (0K)
Collide attempts  = 2909450 (2.91M)
Collide occurs    = 2113906 (2.11M)
Particles stuck   = 0

Particle-moves/CPUsec/proc: 2.56373e+06
Particle-moves/step: 100000
Cell-touches/particle/step: 4.80433
Particle comm iterations/step: 3
Particle fraction communicated: 0.180952
Particle fraction colliding with boundary: 0.185829
Particle fraction exiting boundary: 0
Surface-checks/particle/step: 0
Surface-collisions/particle/step: 0
Collision-attempts/particle/step: 0.969817
Collisions/particle/step: 0.704635

Move  time (%) = 0.0860389 (58.8216)
Coll  time (%) = 0.0556445 (38.042)
Sort  time (%) = 0.00364706 (2.49336)
Comm  time (%) = 0.000400841 (0.27404)
Outpt time (%) = 0.000517696 (0.353929)
Other time (%) = 2.19941e-05 (0.0150366)

Particles: 12500 ave 12813 max 12358 min
Histogram: 3 1 1 0 1 1 0 0 0 1
Cells:      1250 ave 1250 max 1250 min
Histogram: 8 0 0 0 0 0 0 0 0 0
GhostCell: 838 ave 910 max 766 min
Histogram: 4 0 0 0 0 0 0 0 0 4
EmptyCell: 394 ave 466 max 322 min
Histogram: 4 0 0 0 0 0 0 0 0 4
timestep 	    7.00E-9
run 		    100
Memory usage per proc in Mbytes:
  particles (ave,min,max) = 2.05994 2.05994 2.05994
  grid      (ave,min,max) = 1.83113 1.83113 1.83113
  surf      (ave,min,max) = 0 0 0
  total     (ave,min,max) = 3.89107 3.89107 3.89107
Step CPU Np Natt Ncoll temp 
      30            0   100000   100506    70698    273.04554 
      40 0.0076050758   100000     9010     7070    273.04554 
      50  0.015318871   100000     9222     7034    273.04554 
      60  0.023041964   100000     9236     7017    273.04554 
      70   0.03083086   100000     9441     7022    273.04554 
      80  0.038584948   100000     9545     7124    273.04554 
      90  0.046344042   100000     9553     7092    273.04554 
     100  0.054092884   100000     9584     7080    273.04554 
     110  0.061851978   100000     9613     7005    273.04554 
     120  0.069684029   100000     9746     7054    273.04554 
     130  0.077442884   100000     9724     7114    273.04554 
Loop time of 0.0774648 on 8 procs for 100 steps with 100000 particles

Particle moves    = 10000000 (10M)
Cells touched     = 13810984 (13.8M)
Particle comms    = 233619 (0.234M)
Boundary collides = 186429 (0.186M)
Boundary exits    = 0 (0K)
SurfColl checks   = 0 (0K)
SurfColl occurs   = 0 (0K)
Collide attempts  = 936528 (0.937M)
Collide occurs    = 701066 (0.701M)
Particles stuck   = 0

Particle-moves/CPUsec/proc: 1.61364e+07
Particle-moves/step: 100000
Cell-touches/particle/step: 1.3811
Particle comm iterations/step: 1
Particle fraction communicated: 0.0233619
Particle fraction colliding with boundary: 0.0186429
Particle fraction exiting boundary: 0
Surface-checks/particle/step: 0
Surface-collisions/particle/step: 0
Collision-attempts/particle/step: 0.0936528
Collisions/particle/step: 0.0701066

Move  time (%) = 0.037184 (48.0012)
Coll  time (%) = 0.0244756 (31.5958)
Sort  time (%) = 0.00992689 (12.8147)
Comm  time (%) = 0.00482154 (6.22417)
Outpt time (%) = 0.00101784 (1.31394)
Other time (%) = 3.89218e-05 (0.0502445)

Particles: 12500 ave 12668 max 12248 min
Histogram: 1 0 1 1 0 0 1 0 3 1
Cells:      1250 ave 1250 max 1250 min
Histogram: 8 0 0 0 0 0 0 0 0 0
GhostCell: 838 ave 910 max 766 min
Histogram: 4 0 0 0 0 0 0 0 0 4
EmptyCell: 394 ave 466 max 322 min
Histogram: 4 0 0 0 0 0 0 0 0 4

